70 
TRAVELS IN 
overturning the waggons, we now quitted it altogether, and 
encamped on the arid plain at a distance from any water. 
This part of the district is called the Zwart Ruggens or 
black ridges. Except the small plain of our encampment 
there scarcely occurred, in the distance of forty miles, a 
hundred yards of level ground. The roads over the ridges 
were execrably bad, constantly ascending or descending, 
covered with large fragments of loose stones, or carried over 
ledges of firm rock. 
Though vegetation in general was thinly scattered over 
the stony surface, stunted, and languid, yet some of the 
eminences were tolerably well clothed with a species of ett- 
pJiorbia, whose luxuriance of growth shewed it to be con- 
genial to the soil and the situation. The leaves were erect, 
hexangular, and armed with a row of double spines along 
each edge. It appeared to be the same species of which 
Mr. Patterson has given a drawing ; but it is not here con- 
sidered as a poisonous plant, as he has represented it, 
though a very obnoxious one, as by its spines it prevents the 
cattle from picking up any little herbage that may be grow- 
ing about its roots. Another species of enpJiorbia, scarcely 
rising above the surface of the ground, is here also very 
common. From a central corona issue, as so many radii, a 
number of round imbricated leaves, containing, like all the 
rest of this genus, a white milky fluid : the central part of a 
full grown plant incloses not less than a pint. The oxen 
pierce the corona with their incisive teeth, and drink the 
milk ; and it is the opinion of the farmers that they become 
fat by feeding upon it. 'J'hough less astringent than the fluid 
